This invention relates to a method for the preparation of oxydiphthalic anhydrides. The products are useful chemical intermediates for the further preparation of various compounds such as the corresponding dicarboxylic acids and the various derivatives thereof, including for example, the salts, esters, acyl halides, amides, imides, and the like. The oxydiphthalic anhydrides are particularly useful as monomers in the preparation of polyimides, for example by polycondensation with a suitable diamine, such as ethylenediamine or phenylenediamine.
Various methods for the preparation of oxydiphthalic anhydrides have been described in the chemical literature. One such method, shown to be useful in the preparation of oxydiphthalic acids and anhydrides, involves the oxidation of tetramethyl diphenyl ethers. See Kolesnikov, G. S. et al Vysokomol. Soyed, A9, 612-18 (1967); Marvel, C. S. et al, J. Am. Chem. Soc., 80, 1197 (1958); and Latrova, Z. N. et al, Volokna Sin. Polim., 15-24 (1970).
Three Japanese patents to Mitsui describe preparations based on reactions of substituted phthalic anhydrides. Japanese Patent Document No. 80/136, 246 (Chem. Abst. 95:42680) teaches the coupling of 4-nitrophthalic anhydride in the presence of sodium nitrite to form oxydiphthalic anhydride. In Japanese Patent Document No. 80/122,738 (Chem. Abst. 94:83799) Mitsui disclose the reaction of 4-halophthalic acid or anhydride with a base to yield oxydiphthalic anhydride. In Japanese Patent Document No. 80/127,343 (Chem. Abst. 94:191942) the reaction of 4-halophthalic anhydride, Na.sub.2 CO.sub.3 and NaNO.sub.2 in dimethyl sulfoxide to form 4,4'-dihydroxydiphthalylic anhydride is described.
German Pat. No. 2,416,594 (1975) discloses the coupling of 3-nitrophthalic anhydride in the presence of metal nitrites, such as sodium nitrite to form oxydiphthalic anhydride.
Markezich, R. L. and Zamek, O. S., J. Org. Chem., 42, 3431 (1977) describe reaction of 4-nitrophthalimide with potassium fluoride in dimethylsulfoxide to form the corresponding oxydiphthalimide which may be converted by hydrolysis to form the acid and ring closure to form the dianhydride.
U.S. Pat. No. 4,697,023 to Schwartz et al, discloses the preparation of oxydiphthalic anhydrides by reaction of a halophthalic anhydride with water and an alkali metal compound, such as KF, CsF, or K.sub.2 CO.sub.3.